1. Technical Field
The present disclosure relates to an optical lens system for image taking, and more particularly to a miniaturized optical lens system for image taking.
2. Related Art
In recent years, the use of photographic lens assembly is widespread, especially in mobile phone, webcam, car, surveillance camera and electronic entertainment industry. The photo-sensing device, e.g. a sensor, of an ordinary photographing camera is commonly selected from a charge coupled device (CCD) and a complementary metal-oxide semiconductor (CMOS) device. In addition, with the advance of semiconductor manufacturing technology enabling the miniaturization of pixel size of sensors, the resolution of a compact optical lens assembly is gradually increased so there are increasing demands for compact optical lens assemblies capable of generating better quality images.
To obtain a wide field of view, there is a so-called inverse telephoto structure adopted in a conventional photographic lens assembly having a wide field of view. In order to improve the image quality and miniaturize the overall size, a photographic lens assembly consists of three lens elements is disclosed. For example, U.S. Pat. No. 7,397,612 discloses an optical system for taking image consists of three lens elements including, from the object side to the image side, a first lens element with negative refractive power, a second lens element with positive refractive power, and a third lens element with positive refractive power. However, this assembly generates the excessive curvature radius of an object-side surface of the first lens element and the excessive curvature radius of an image-side of the first lens element, so the excessive high order spherical aberration is obtained and the difficulty of lens manufacturing is increased.
To sum up, a photographic lens assembly having a wide field of view without the excessive high order spherical aberration is urgently needed.